Sider

Sider is a multi-model AI assistant that follows you across the browser, the desktop and your phone, rather than living on a single chat website. It started as a browser sidebar that opens alongside whatever page you are reading and has grown into a cross-platform assistant with Chrome, Edge and Safari extensions, native Mac and iOS apps, and a web app that share one account and history.

Its defining trait is breadth of model access. A single subscription reaches the GPT, Claude, Gemini, Grok, DeepSeek, Kimi, GLM and Qwen model families, and you can switch between them mid-conversation or compare answers side by side. A routing layer called Sider Fusion picks a model per request when you would rather not choose, which is useful when cheap models handle most turns and only some need a frontier model.

Around the chat sit the features that make it a work tool. Reading support summarises, translates and explains a page, a PDF or an image; writing support drafts and rewrites in a chosen tone; an image generator handles text-to-image; and "Chat with Content" ingests 30+ file formats and URLs so you can question your own documents. Wisebase is a built-in knowledge base that keeps uploaded files and saved pages queryable over time, and Sider Claw is an agent mode that runs multi-step browsing jobs — researching, comparing products across sites, extracting data and returning a table, report or draft.

Sider is free to download with paid tiers unlocking higher usage and the frontier models. The iOS app requires iOS 17 or later and holds a 4.7-star average across roughly 4,300 ratings; the company behind it is Vidline Inc. It suits researchers, students and knowledge workers who read heavily in the browser and want one assistant — and one bill — instead of separate subscriptions per model vendor.